TELEPHONE NETWORK VOICE RECOGNITION AND VERIFICATION USING SELECTIVELY-ADJUSTABLE SIGNAL THRESHOLDS

摘要

A method for enabling a caller to obtain access to one or more services via a telephone network by speaking a password begins by establishing at least one predetermined threshold value for a speaker verification signal. For each spoken character of the password, the method generates a set of parameters using a voice verification feature transformation. After entry and recognition of the password, the sets of parameters are used to generate a speaker verification signal for the password (step 78). Upon the occurence of a predetermined call condition, the predetermined threshold value is adjusted to increase the level of security in the verification algorithm. If the speaker verification signal for the password has a predetermined relationship with respect to the adjusted threshold value (84), the caller's identity is accepted (88). If not, the caller may be asked (90) to answer certain personnal questions before his or her identity is accepted.